FIG. 1 is a front view of a conventional apparatus for injecting plasma in the atmosphere. FIG. 2 illustrates the conventional apparatus of FIG. 1 viewed from direction A.
As shown in FIGS. 1 and 2, a conventional apparatus for injecting plasma in the atmosphere is manufactured by coupling a pair of dielectric panels 3 and 3 to a gas supply portion 4 and forming plate-type electrodes 2 and 2′ on the surfaces of the dielectric panels 3 and 3′ such as to be opposite to each other. In this plasma injecting apparatus, when a high frequency power supply portion 1 applies high frequency power to both the plate-type electrodes 2 and 2′, and gas flows between the dielectric panels 3 and 3′, the gas turns into plasma which is injected from the ends of the dielectric panels 3 and 3′. This plasma is injected into an object, such as a liquid crystal display (LCD), a plasma display panel (PDP), a wafer, or the like, to clean the object.
However, plasma comprised of charged particles is strongly prone to be bound between the dielectric panels 3 and 3′ due to an electrical field between the plate-type electrodes 2 and 2′. As a result, even if the gas supply portion 4 continuously supplies gas, plasma is not properly injected from the dielectric panels 3 and 3′.
To overcome this problem, an effort has been made to increase the amount of plasma by using a high voltage and higher frequency. However, the use of a high voltage causes generation of an arc between plasma and the outside, an increase in the power consumption, and the like.